Modulating capacity transformer with three-phase imbalance resistance

Abstract

The invention discloses a modulating capacity transformer with three-phase imbalance resistance. The transformer comprises three phases of low-voltage windings, wherein each phase of low-voltage winding comprises a first coil assembly and a second assembly having equal turns. According to the low-voltage windings of the modulating capacity transformer, a traditional three-section winding mode is broken through, only two groups of coils having equal turns is adopted to wind, and with the structure, Yzn11 connection of the modulating capacity transformer can be adopted in small capacity. The connection mode has a relatively strong capability of bearing imbalance loading, namely relatively strong single-phase power supply capability, which is particularly suitable for places, such as rural areas and mountain areas with difficulty in three-phase loading balance. Furthermore, two groups of turns are equal, and can be determined arbitrarily, so that a design for saving most materials can be selected, and two groups of windings are easily distributed to guarantee a high window filling coefficient.

Description

technical field [0001] The invention belongs to the technical field of transformer equipment in the electric power industry, and in particular relates to a three-phase unbalance-resistant capacity regulating transformer. Background technique [0002] The on-load capacity regulating transformer is a transformer with two rated capacities. According to the size of the load, use the corresponding capacity regulating switch to switch the connection mode of the transformer winding without cutting off the power supply, and then realize the transformer between two different capacities. switch between. [0003] At present, on-load capacity regulating transformers generally use a structure in which the high-voltage side winding is D-Y conversion and the low-voltage side winding is parallel-serial conversion. The parallel-serial conversion of the low-voltage side winding needs to divide the low-voltage winding into three sections. This three-section The capacity regulating transformer...

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Problems solved by technology

[0003] At present, on-load capacity regulating transformers generally use a structure in which the high-voltage side winding is D-Y conversion and the low-voltage side winding is parallel-serial conversion. The parallel-serial conversion of the low-voltage side winding needs to divide the low-voltage winding into three sections. This three-section The capacity regulating transformer of the low-voltage winding adopts Yyn0 connection when the capacity is small, and as the power of single-phase electrical equipment increases and the number increases, factors such as temporary power consumption, line faults, and seasonal power consumption cause power distribution problems. When the three-phase load of the transformer is unbalanced, the Yyn0 connection will cause the following problems: (1) increase the line loss and transformer loss; (2) reduce the output of the transformer; (3) the neutral point will be displaced, the phase voltage will rise to the line voltage, Burn out electrical equipment; (4) The voltage at the transformer outlet is unbalanced, the three-phase voltage deviation at the user end is large, and the voltage quality cannot be guaranteed; (5) Harmonic voltage is generated to pollute the power grid

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